Non-Human Primate (NHP) Bite Protocol

Infectious diseases
NHS Lothian
  • Patients bitten/injured by Non-Human Primates (NHP) are at risk of bacterial skin and soft tissue infection, tetanus, rabies and herpes B virus infection.  
  • Even minor injuries carry risk and warrant a thorough risk assessment. 
  • This protocol refers to assessment of NHP injuries.  
  • Any patients presenting with fever, flu-like symptoms, vesicles at site of injury or signs of encephalopathy following an injury from a non-human primate should be immediately discussed with the ID registrar on-call 
  • First point-of-contact for medical assessment should be the Emergency Department. Please contact infectious diseases (ID) if there are concerns following assessment.  

Summary of management

1. Wound care

Wound care should happen at the time of injury and be repeated at medical assessment.

Wash wound thoroughly with:

  • chlorhexidine 4% solution OR povidone-iodine 10% antiseptic solution 
  • then irrigate for 15 minutes with Water for Irrigation

If injury eye/mucous membrane:

  • irrigate for 15 minutes with Water for Irrigation

2. Take history:

Injury
  • Date & Time
  • Bite, scratch or mucosal exposure
  • Location on body
  • Depth of wound (deeper than dermis or superficial)
Initial management
  • Was there adequate wound care at time of injury (as per Step 1)
Details of animal source
  • Species
  • Country of origin. Date of arrival in UK (if relevant)
  • NHP behaviour/health (see Herpes B section below)
  • Contact with other NHPs (if non-wild NHP)
  • Has the animal been assessed by a vet where relevant (see Herpes B section below)
Patient details
  • Rabies vaccination status
  • Tetanus vaccination status
  • Past Medical History (PMH) - specifically if immune compromised

  

3. Management and follow up of specific infection risks

Management:

 

Follow up:

  • Herpes B - dependant on risk assessment, follow up at RIDU may be required
  • Tetanus - usually nil
  • Rabies - dependant on risk assessment, follow up at RIDU may be required
  • Bacterial skin/soft tissue infection - usually nil

Herpes B Virus Risk Assessment and Management

(For macaque exposures only – not relevant for non-macaque primates) 

⚠️ Why It Matters: 

  • Herpes B virus (Cercopithecine herpesvirus 1) can cause severe encephalitis in humans. 
  • ~75% mortality if untreated; early post-exposure prophylaxis (PEP) reduces this to ~20%. 
  • Most human cases have been acquired from asymptomatic macaques. Any exposure to a potentially infected animal therefore requires careful risk assessment. (Cohen, Huff) 
  • Even minor exposures can be fatal. 

 

Step 1: Assess Risk associated with source non-human primate 

Table 1: Macaque Type / Previous Herpes B Serology Result

Risk Level
Ill macaque, lesions present, or known shedding Herpes B  High
Non-Mauritian or unknown origin – untested or not had final 3-month test Possible
Mauritian or Gibraltarian macaque (even if untested)  Negligible
Tested Herpes B negative (e.g. 3-month serology) Negligible
Wild macaque (e.g. temple exposure) Negligible

Outcome of risk assessment:

  1. If negligible risk (see table 1), no further risk assessment is needed. Offer patient reassurance that the risk is negligible but advise them to seek medical attention if they develop: vesicles at site of the bite; fever; flu-like symptoms; or signs of encephalopathy within 5 weeks.
  2. If ‘possible’ or ‘high’ risk proceed to step 2. 

 

Step 2: Assess injury risk (based on recommendations from Cohen et al) 

Table 2: Source Animal Score
Healthy macaque  0
Macaque that is ill or immunocompromised  1
Macaque that is known to be shedding herpes B virus 1
Macaque that has lesions compatible with herpes B virus disease  1
Test results from vet indicates macaque is infected with herpes B virus 1

 

Table 3: Injury type / Site Score
Skin intact  0
Mucosal exposure / Minor laceration (except to the head, neck or torso)  1
Needlestick involving blood / exposure to objects contaminated with body fluid / infected cell culture  1
Deep bite in any location / Any head, neck, or torso injury  2
Needlestick / exposure to objects contaminated with tissue/fluid from nervous system, eyelids or mucosa (oral/genital), lesions suspicious for B virus  2
Wound cleaning: Inadequate +1 if applicable

 

Step 3: Calculate total score to guide management (add scores from table 2 and 3) 

Total Score Risk Level Action
0 Low ❌ No prophylaxis, give advice, no follow-up 
1 Moderate

 

❌ No prophylaxis, but follow-up at weeks 1, 2 & 4 by ID team 
≥2 High

✅ Start PEP: Valaciclovir 1g 8hrly oral or Aciclovir 800mg 5 times daily oral for 14 days  (dose adjustment required in renal impairment or obesity - see BNF)

Start as soon as possible, ideally within 5 days of exposure 

 

📞 Urgent Follow-Up and Referral 

  • ID team arranges: 
    • Follow-up at 1, 2, and 4 weeks for moderate/high risk 
    • Monitoring for symptoms within 5 weeks of inury (see list below).

 

🚨 If Symptoms of Herpes B Infection Develop 

Symptoms include: Fever, rash, altered mental status, weakness, headache. 
  1. Immediate ID review (pager 8161 or via switchboard) 
  2. Discuss with Colindale Virus Reference Department R.E. sample handling and antiviral therapy 
  3. Initiate IV antivirals (dose adjustment required for in renal impairment or obesity. If ganciclovir considered, please discuss with pharmacist): 
    • Without CNS signs: Aciclovir 12.5–15 mg / kg* IV 8hrly or Ganciclovir 5 mg / kg IV 12hrly.
    • With CNS signs: Ganciclovir 5 mg / kg IV 12hrly  

*This is an off-label dose as per: https://doi.org/10.1086/344754 (full reference in reference section)

 

Tetanus Risk Assessment & Management

All NHP bites are considered tetanus-prone wounds. 

Patient Status Action

✅ Received full 5-dose primary tetanus vaccination AND last dose within 10 years 

 ➡️ No treatment required 

✅ Received full 5-dose course, but last dose >10 years ago 

 ➡️ Give one reinforcing dose of tetanus vaccine 

❓Unknown or incomplete vaccination history (e.g., born before 1961, or unclear records) 

➡️ Give one dose of tetanus vaccine

AND

➡️ Give Tetanus immunoglobulin (TIG) by intramuscular (IM) injection

  • 250 IU for most cases
  • 500 IU if more than 24 hours have elapsed or there is risk of heavy contamination or following burns
  • This preparation is available in 1ml ampoules containing 250IU.

Human normal immunoglobulin (HNIG) can be used as an alternative in the absence of TIG. More detailed information on the products available, dosage (based on potency testing) and administration of these products is available in Table 5 in the UKHSA tetanus guidance.

For full tetanus vaccination guidance see: Tetanus: the green book, chapter 30 - GOV.UK

 

Rabies Risk Assessment & Management

Rabies risk in NHP varies by country of origin:  

Origin Risk of Rabies
UK None, unless they have had contact with imported NHPs
Mauritius No risk of rabies (as of 2025) 
Other Varies by country: check here.  

➡️ Risk assess and manage as per Rabies Post Exposure Risk Assessment

  • Please contact infectious diseases on-call if risk assessment not clear or recommends post-exposure rabies vaccination/HRIG. 

 

Bacterial infections

Follow NHS Lothian antimicrobial guidelines for management of animal bites (For prophylaxis use the recommendations for human bites). 

 

References and abbreviations

For further information on assessment and management of herpes B prone injuries:

  • PHE, Follow-up of monkey bites. PHE publications gateway number 2016652. March 2017.  
  • Barkati S, Taher HB, Beauchamp E, Yansouni CP, Ward BJ, Libman MD. Decision tool for herpes B virus antiviral prophylaxis after macaque-related injuries in research laboratory workers. EID 25 (9) 2019. 
  • Rohman M. Macacine herpes virus (B virus). Workplace health and safety. 64 (1) 2016. 
  • Elmore D, Eberle R. Monkey B virus (Cercopithecine herpesvirus 1). Comparative medicine 2008. Vol 58 No 1 Pages 11-22. 
  • Engel GA, Pizarro M, Shaw E, Cortes J, Fuentes A, Barry P, Lerche N, Grant R, Cohn D, Jones-Engel L. Unique pattern of enzootic primate viruses in gibraltar macaques. Emerg Infect Dis 2008 Jul; 14(7): 1112-1115.  
  • Jeffrey I. Cohen, David S. Davenport, John A. Stewart, Scott Deitchman, Julia K. Hilliard, Louisa E. Chapman, B Virus Working Group, Recommendations for Prevention of and Therapy for Exposure to B Virus (Cercopithecine Herpesvirus 1), Clinical Infectious Diseases, Volume 35, Issue 10, 15 November 2002, Pages 1191–1203, https://doi.org/10.1086/344754
  • Guidance on the management of suspected tetanus cases and the assessment and management of tetanus-prone wounds - GOV.UK [accessed Jan 2026]
  • Green book chapter 30 - Tetanus [accessed Jan 2026]

 

Abbreviations

 

BNF: British National Formulary

CNS: Central nervous system 

C&S: Culture and sensitivity  

HNIG: Human Normal Immunoglobulin

HTIG: Human tetanus immunoglobulin

HRIG: Human rabies immunoglobulin  

ID: Infectious diseases  

MDT: Multi-disciplinary team  

NHP: Non-human primate 

NHSL: NHS Lothian  

PCR: Polymerase chain reaction  

PEP: Post-exposure prophylaxis  

PHE: Public Health England  

RIDU: Regional infectious diseases unit 

SSTI: Skin and soft tissue infection 

Editorial Information

Last reviewed: 26/01/2026

Next review date: 25/01/2028

Author(s): Dr Muge Cevik, Dr Oliver Koch, Dr Jenny Poller.

Version: 2.3

Approved By: UHD Drug and Therapuetics Committee

Reviewer name(s): Dr Oliver Koch, Dr Jenny Poller, RIDU Guidelines Group.